Abstract
A space chamber was made for testing the electron bombardment type ion rocket engines. The chamber was evacuated with a 26-inch oil diffusion pump followed by a 6-inch one. The ion beam was accelerated up to 5 kV and the beam current was in the range of 0-100 mA. The gas desorption induced by ion bombardment on the LN cooled wall is mainly discussed. The experimental result is also described on the other problem whether or not the oil diffusion pump is available to use for evacuation of mercury vapor. With cryopumping of the LN cooled wall, ion rocket engine could be operated in the pressure range of 10-6 Torr.
